By default, all QSFP+ ports on the EX4300 chassis are configured as virtual chassis ports (vcp). VC minimal (recommended) requirement is two ports, meaning that two out of the four ports can be used as regular 40 Gbps interfaces and/or for uplink purpose. Let’s assume we want to use the port #0 and 1 as… Read More »
If you are using the WebUI to manage your Juniper SSG / ScreenOS device, you probably encountered the following error accessing the page lately : ERR_SSL_VERSION_OR_CIPHER_MISMATCH If you use a browser that allow SSLv3, you will be able to access the device. However as we all know the weakness of this protocol, it isn’t ideal… Read More »
You probably encountered the following error if you are a fan of using the Juniper SSG/ScreenOS WebUI using a “modern” browser : ERR_SSL_VERSION_OR_CIPHER_MISMATCH Well, since the latest clustered SSL exploits, the vast majority of browsers decided to disable some protocols and ciphers for everyone’s safety. To work around this issue, you may use the following… Read More »
You probably have seen the following on your Juniper JunOS device : dcd: ae60 : Warning: aggregated-ether-options link-speed no kernel value! default to 0 dcd: ae60 : aggregated-ether-options link-speed set to kernel value of 1000000000 This mean that your aggregated interface (ae) does not have any link-speed statement. By the book, this statement should be… Read More »
Having the red alarm led on but nothing is wrong with your JunOS powered Juniper device? First, look out what alarm is triggered by issuing the following command :
show chassis alarm
If absolutely nothing is really wrong, you will see the following alarm : Alarm time Class Description 2016-01-20 07:11:59 UTC Major Management Ethernet Link Down… Read More »
Having the following output message while trying to create a VLan outside higher than 1000 on your Cisco device?
% Failed to create VLANs 2991
Extended VLAN(s) not allowed in current VTP mode.
%Failed to commit extended VLAN(s) changes.
This mean that you are running VTP mode 1 or 2, which only support VLan range between 1 – 1000. To be able to create anything outside of that scope, you need to run VTP… Read More »
You probably noticed that rapid pings toward a JunOS device result in a loss of packet as the example shown below. In our case we are issuing the ping from a Cisco router : Sending 100, 500-byte ICMP Echos to 10.204.100.1, timeout is 2 seconds: Packet sent with a source address of 10.204.100.1 .!!!!!!!!!.!!!!!!!!!.!!!!!!!!!.!!!!!!!!!.!!!!!!!!!.!!!!!!!!!.!!!!!!!!! .!!!!!!!!!.!!!!!!!!!.!!!!!!!!!… Read More »
As a long time OpenVPN user, the major annoyance I faced with this software is obviously the inflexible behaviour of the Windows client, which is just fine if you are running/connecting to a remote server. However, if you are actively managing thousand servers and networks, you may end up at some point having the need to… Read More »
Here is a chart for the various DWDM optic channels below. Wavelenght band overview : O-Band : 1270nm to 1370nm E-Band : 1371nm to 1470nm S-Band : 1471nm to 1530nm C-Band : 1531nm to 1570nm L-Band : 1571nm to 1611nm Channel Wavelength (nm) Frequency (THz) 72 (DWDM Channel C72) 1520,25 197,20 71 (DWDM… Read More »
If you have a Cisco ASR or smaller service router, you probably noticed that the device have a dedicated management interface. This special interface is a mapped to a Vritual Routing and Forwarding (VRF) instance. VRF allow multiple routing tables to coexist within the same router. You will first ensure that you have the VRF… Read More »